Studying On Uncertainty In Life Cycle Assessment Of Rare Earth Magnetic Material

With the promotion of energy conservation and emission reduction in the country,green development has become the mainstream of enterprises development.And green production is more impotant for manufacturing enterprises,especially for rare earth magnetic material manufacturing enterprises.However,there are many environmental problems in the production process of rare earth magnetic materials.For this reason,the rare earth magnetic material is selected for research,so as to improve and optimize the green production level of the enterprise from its root source.As a representative of rare earth magnetic materials,the application fields and requirements of NdFeB magnetic materials are expanding.Among them,Sintered NdFeB magnetic materials(Sintered NdFeB)account for about NdFeB 90.00% of the total output,Sintered NdFeB is the magnetic material with the best magnetic energy product and the widest application range on the market.Life Cycle Assessment(LCA)is a method for assessing environmental impacts of a product throughout its production,use,and recycle.And it is a popular method in evaluating environmental impacts.Therefore,it is necessary to evaluate the environmental impacts of Sintered NdFeB with LCA method.There are many uncertainties in the LCA study,and these uncertainties will determine the accuracy and reliability of the LCA results.Therefore,it is important to analyze the uncertainties in LCA.1 kg Sintered NdFeB was selected as the research object,and the environmental impacts of “from cradle to gate” were analyzed in the LCA system,and the uncertainty analysis was conducted.In the LCA study,the calculating way based on the correlation coefficient of E(Egalitarian)in the ReCiPe 2008 impact assessment method.And it identified environmental impacts and phases that have greater impacts on the environment.In the uncertainty analysis,the reliability of LCA results is analyzed from three aspects of data,results and evaluation methods.The Data Quality Indicator(DQI)and the Halton Quasi-Monte Carlo(HQMC)are combined to analyze the uncertainties of the Sintered NdFeB raw data and inventory data.IMPACT 2002+,CML 2001,and TRACI were selected to calculate the environmental impacts of Sintered NdFeB “from cradle to gate”,and the results were compared with the results of ReCiPe 2008 method.The results of LCA research show that fossil fuel consumption,human toxicity,particulate matter formation and climate change are important impact categories in the Sintered NdFeB production process,and their proportion is 56.86%,26.03%,10.84%,5.21% in turn;the selection of Sintered NdFeB production(34.03%),electrolysis(29.64%),hydrogen explosion(12.54%),extraction separation(11.34%),and smelting(7.13%)have more serious impacts on the environment,especially in the selection.The conclusions of the uncertainty analysis show that the quality of most inventory data is up to standard,and the quaility of the resulting data is also up to standard.And the results of the four evaluation methods were consistent under the same metric,which indicates that evaluation results of the ReCiPe 2008 method is reliable.Therefore,LCA research results are reliable.Based on the results of LCA research and the requirements of green development,rare earth magnetic material manufacturing enterprises can carry out green development work in fossil fuel consumption,human toxicity,particulate matter formation and climate change.From the perspective of life cycle,the key pollution factors causing serious impacts on fossil fuel consumption,human toxicity,particulate matter formation and climate change are analyzed.Combining the development requirements of rare earth magnetic material manufacturing enterprises,some improvement measures were proposed in oreder to improve the green development of rare earth magnetic material manufacturing enterprises.